how do i do these two. irene bought a typewriter at rocklanes in 1988 for $200.In 1999, she bought the same model of typewriter for $120.What is the percent decrease in the price of the typewriter. denise bought a typewriter at rocklanes in 1984 for $500. In 2000 , she bought the same model of typewriter for $440. What is the percent decrease in the price of the typewriter?